One
before Many by eXternal

Answers
to ten clues are thematically reduced by a letter. The redundant
letters when
rearranged suggest a pattern to be highlighted in the finished grid.
All other
clues contain a misprint in the definition. In clue order the correct
letters
spell out a relevant quotation. The title suggests the one unique
letter to be
changed within the grid. Three extra clues without definition reveal
answers
sharing common ground, this should aid the solver. All enumeration
refers to
answers, not grid entries.

Across
1 Thin
batteries supplied
regularly to doctors for instrument often used with thin (6)
6 Will's
to stir and turn over
embraced by his queen intimately (6)
10 Visit
topless musician
displaying sweet thickness (8)
12 In
demand, reliable stock to be
rotated (7)
13 Monkey
and sloth following
goose (6)
14 Rag's
article and column had
taste (8)
16 British
crook with the police
(4)
17 Family
in recession getting
satellite, that's extremely good (7)
18 A
knight's framed by the parson
close to king (5)
20
Scientist from Iceland is said
to be very angry (5)
22 Crafty
deer losing head of herd
(4)
24 Lad
reverses over his sister
and shows signs of dazing (4)
26 Parts
of curvy artistic
figures, having removed uniform, receive love (5)
28
Manfully oppose bidder after
bronze (6)
30 Moping
in pain, cramp's
starting in punctured side (7)
31 Arm
smashed brat hard (3)
33 Opal
stops volatile ex
disappearing with son (8)
35 Accept
wags associated with
another one, anonymous and concerning (5)
36 One set
about guarding that
foremast (7)
37 Eastern
cops might contain this
troublesome teenager (5,3)
38 Pub on
marsh is about one grand
(5)
39 People
benefitted from number
of Cockneys playing pieces (7)

Extra clues:
Some anger management (6)
I'm about to have tea with the Spanish (7)
Article doctor read with son (7)

To
enter this
competition, send your entry as an
image or in list format, indicating the highlighted entry, to
quiz.man@ntlworld.com before the 8th October
2012. The first correct entry drawn from the hat will receive a copy
of one of the Chambers Brewer's Dictionary of Phrase and
Fable
which has been donated
by Chambers.